"It's me," he says, and I'm thinking: who are you? "It's me, mate." I look again and it's Jason. "It's all right," he says, "my dad didn't recognise me when he first saw me on the out. It all drops away," and he shakes his shoulders, arms, and fingers as if he were getting rid of something, "when you get out."

I remember him, shoulders slumped, plodding up the corridor when he'd finished beating me up in philosophy. "Be good," I would always say to him. It was what my mother said whenever I was going off somewhere. And then he'd turn round and say, deadpan: "Be lucky." That was years behind us and Jason is here, now, at the conference of the British Society of Criminology. We are both giving papers.

We have one of those conversations: do you remember so and so, what's he doing now, don't know, don't know. Oh Alec, yeah, he's a chippy, got two kids now. Remember Joe? He's back. Kenny? Yeah, he's back as well.

Not everybody works out as well as Jason. I tell him about speaking at a Prison Education Trust do. "You could tell the ex-cons; they were the ones in suits, collar and tie, all polished up." "Yeah," says Jason, "I try to dress down." Here he is, though, in his suit. "I think it's a bit of a yearning to be respectable," he says.

In education, we're supposed to have an eye to the future and there's a lot of talk about employability, but it seems to me that men like Jason and Alec are a bit thin on the ground. More typical are the guys who expect to be going out and back to drugs or crime or the dole, or those who are not going out at all, or the old, the infirm, the mentally ill. They could all do with a bit of education. Why? What for? For happiness, I suppose.

It might not be quite the thing to confess to these days, but I quite like the idea of making the guys happy. Better than grinding on to them about a future that they can't have anyway, a future that's full of work. We seem to forget, sometimes, that most people don't like work and do as little of it as possible. "Take this job and shove it," as Waylon Jennings used to sing.

And so I plan that when I get back from my hols to talk about art and beauty, about philosophy of mind, we are going to wonder if there is a table over there and talk about Plato's Theory of Forms. Even if they were employable before, they won't be when philosophy and I have done with them.

No, don't talk to me about common sense, about being reasonable, about reform. I've had people in my class who were actively planning to become heroin addicts when they got out. It's the sort of thing that tends to take the wind out of my liberal sails, but they did like philosophy with me and I liked philosophy with them.

It may well be that 12 years of philosophy and prison have made me daft or corrupt or both, but after I have given my paper I have lunch with Jason and he tells me that it was a bit like Adorno, whom I haven't read but he has, and then he explains to me Hobbes's notion of diffidence and how he is applying it to modern ideas in penology. And I know that I am right and that everybody else is wrong. Again.